This invention relates to a fine metering apparatus for the final filling of containers with flowable goods, particularly coffee and is of the type which has a housing defining a material storage chamber, a discharge unit connected to the housing and a rotatable metering member which is accommodated in the discharge unit and which is coupled to a motor by a drive shaft.
U.S. Pat. No. 4,662,409 discloses a fine dosing apparatus, particularly for crystallized sugar. The apparatus includes a housing with a storage for the sugar and a tubular discharge unit connected to the housing. The discharge unit accommodates a conveyor screw which is oriented horizontally and is rotatable about its longitudinal axis. The conveyor screw is connected with a motor by means of a drive shaft. At the outlet end of the tubular discharge unit there is arranged a pre-dosing chamber having a rotary slide.
Swiss Pat. No. 627,985 shows another fine metering apparatus for crystallized sugar which has a compartmentalized wheel rotatable about a horizontal axis and serving as a metering member. The compartments of the wheel are formed by axial grooves provided in the wheel periphery.
In packaging coffee frequently the same packing machine is used for packing ground coffee or packing coffee beans. In such packing machines, according to conventional arrangements, a compromise had to be found for the supplemental fine dosing apparatus which introduces the last, accurately metered portion of material to obtain the desired overall weight for the package. Because ground coffee and unground coffee beans behave differently, the known dosing devices were not optimal for the packaging of either form of coffee.